Safety cranking attachment for explosive-engines.



FL BRAYER & s. L. LONG.

SAFETY CRANKING ATTAGHMEN T FOR EXPLOSIVE ENGINES.

APPLICATION FILED APR. 12, 1911.

Patented July 2, 1912.

COLIIMBIA PLANOGIIAPH (0-- WMHINLI'ION. D. C.

FRANK BRAYER AND SIDNEY L. LONG,

0F MINNEAPOLIS, MINNESOTA; SAID BRAYER ASSIGNOB T0 GUIDO J. ALBRECHT, OF MINNEAPOLIS, MINNESOTA.

SAFETY CRANKING ATTACHMENT FOR EXPLOSIVE-ENG-INES.

Specification of Letters Patent.

Patented July 2, 1912.

Application filed April 12, 1911. Serial No. 620,688.

To all whom it may concern:

Be it known that we, FRANK BRAYER and SIDNEY L. Lone, citizens of, the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Safety Cranking Attachments for Explosive-Engines, of which the following is a specification.

Our invention relates to a safety cranking attachment for explosive engines by which the engine may be cranked to start the same without any possibility of a back stroke of the engine shaft, caused by misfiring, being conveyed to the cranking handle to throw the same violently backward, as is the condition prevailing with the usual cranking attachment for engines of this type.

The object of our invention is to provide a cranking attachment having the above characteristics which shall be simple in construction, economical to make and apply to engines already constructed and at the same time perfectly easy of operation, wherein a back stroke of the engine shaft caused by misfiring will operate automatically to disconnect the crank from said engine shaft at practically the same instant of said misfir- 51 further object of our invention is to provide a device of this character wherein the members thereof are positioned within a dust-proof casing, and providing a construction and arrangement of parts suchas will render the device certain and simple of operation and at the same time properly secure said parts from wear and breakage so that the attachment will have a relatively long working life.

The full objects and advantages of our invention will appear in connection with the detailed description thereof and are particularly pointed out in the claims.

In the drawings illustrating the applicacation of our invention in one form-Figure 1 is a front elevation of an engine casing having our cranking attachment secured thereto, the casing of the cranking attachment being removed to better show the parts. Fig. 2 is a similar view of the cranking attachment with the connecting disk removed. Figs. 3 and 1 are sectional side views showing the parts in two different positions. Fig. 5 is a section on line 5-5 of Fig. 3 viewed in the direction of the arrows.

tends inwardly toward and 18, be forced outwardly on the To the front of the engine casing 6 a tubular member 7 is secured by means of bolts 8 passing through lugs 9 on the tubular memher 7 and fastened into the front wall of said engine casing 6, a dust-proof casing 10 being secured so as entirely to surround said cranking device by means of screws or bolts extending into a thickened rim 11 on the member 7. The tubular member or drum 7 is provided about the exposed periphery thereof with a series of teeth 12 each having one face thereof lying in one of the elements of the cylinder and the other face beveled away therefrom, as clearly shown in Fig. 3. The engine shaft 13 extends centrally through the drum 7 and is provided at the bar 14. A second drum 15, of the same diameter as the drum 7, is centrally and loosely mounted upon the shaft 13 by means of a web 16 and collar 17, as shown in Figs. 3 and 4:, a portion of the drum extending upon each side of the web 16. That portion of said drum 15 which exthe drum 7 is provided around the periphery thereof with a series of teeth 18 having straight and beveled faces similar to the faces of the teeth 12 on the drum 7 excepting that the beveled portions of the teeth 18 extend in the opposite direction from the similar faces of the teeth 12.

A coil spring 19 encircles the shaft 13 and extends between the web or diaphragm 16 and the front of the engine casing, or a similar web forming a backing of the drum 7 where it is deemed desirable to employ such a member, said spring normally pressing the drum 15 outwardly to hold the web 16 in contact with the clutch pin 14 and the teeth 12 and 18 on the drums 7 and 15, respectively, out of engagement. The two drums 7 and 15 and the teeth 12 and 18 on the peripheries thereof are therefore so related that by pressing inwardly upon the drum 15 against the force of the spring 19 the teeth 18 of the rotatable drum 15 may be brought to engage between the teeth 12 of the fixed drum 7, as shown in Fig. 4. When in this position the rotatable drum 15 will be held fixed from rotation in one direction, and may rotate in the other direction, but in so rotating will, through the action of the beveled faces of the teeth 12 shaft 13.

free end thereof with a clutch crossthe drum15 is forced started so that the shaft 13 is independently 27 and disk 20, said disk 20 will be clutched to the drum 15 causing said drum torotate so that engagement of the beveled faces of the teeth 12 and 18 will force said drum l5 outwardly and separate the clutch pin from the clutch faces 32. Various means of causing said disk 20 to be clutched to the drum 15 on backward movement of said disk may be employed with advantage and fall'within the scope of our invention, but we have found the following construction to be properly responsive and therefore to give satisfactory results. The inner peripheral surface of the drum with a series of close fine corrugations 34, as shown in Fig. 5. The cavity 31 is surrounded by an extension 35 forming a sort of collar protruding inwardly from the disk 20. Pivoted at the points indicated by reference characters 36 are a series of fingers 37 normally forced outwardly by springs 38 positioned between said fingers 37 and depressions 39 in the collar 35. Pins 40 are provided on the disk against which the fingers 37 will abut when said disk is not assembled in the drum, the points 41 of said fingers in such case extending beyond the periphery of the disk, as shown in Fig. 5. The fingers 37, being held in aposit-ion extending at a large angle from the radial lines of the disk, will, when the disk is assembled within the drum 15, engage the knurled surface 34 thereof so that said disk may rotate freely in the direction opposite to said angular disposition of the fingers 37, but when said disk is attempted to be rotated in the other direction all of the beveled ends 41 of the fingers 37 will engage in corrugations 34 and instantaneously clutch said drum 15 to rotate with the disk 14.

It will thus be seen that the first results of back firing when an explosive engine is being cranked will be to start to rotate the drum 34 in conjunction with the disk 20. But the immediate effect of this is to cause the engaging beveled faces of the teeth 12 and 18 to thrust said drum 15 outwardly and unclutch the shafts 13 and 27. The manner of operating the device is identically like that of the cranking attachments in common use. The operator simply forces the clutch faces 32 into engagement with the clutch pin 14 against the pressure of the spring 19 and cranks the engine in the ordinary way. Upon a misfiring and back stroke, however, the crank remains in his hand disconnected from the engine shaft and he is conscious of no shock whatever, the more violent the backward stroke of the shaft 13 may be the more certain will be the disconnection of the cranking shaft without strain or shock to the operator of any sort.

We claim:

1. An explosive engine having a shaft WVithin the outer portion of the drum .15 a disk 20 is secured, so as to rotate freely within said drum, by means of a slot 21 and a series of pins 22 on the ends of screws 23 screwed into the walls of the drum 15, the form shown having been found satisfactory for the purpose, although other means of assembling the disk 20 within the drum 15 are contemplated and fall within the scope of our invent-ion. Centrally disposed in said disk 20 is abore 24 surrounded by an extension collar 25 within which is secured by means of screws 26 or otherwise a shaft 27 having on the free end thereof a crank handle 28, said shaft being additionally supported by a bearing 29 on a bracket 30 secured to the framework supporting the engine. The bore 24, as shown in Fig. 3, is of the proper diameter to receive the end of the shaft 13 and opens centrally into an enlarged cavity 31 of a diameter sufficient to receive the clutch pin 14, the cavity 31 being provided with a pair of oppositely disposed clutch members having square faces 32 and beveled faces 33, as clearly shown in Fig. 3, so that when the disk 20 along with inwardly into the position shown in Fig. 4 the opposite ends of the clutch pin 14 will engage, on opposite sides of said ends, the clutch faces 32, whereby rotation of the shaft 27 in one direction will rotate the shaft 13 while rotation in the opposite direction will result in immediate unclutching of the parts. That is, the two shafts are clutched together so that rotation of the shaft 27 in the active direction will correspondingly rotate the shaft 13, and if action of the engine is rotated in the same direction this action will result in unclutching of the parts. This or a substantially similar construction, is the clutching mechanism ordinarily employed in connection with devices for cranking explosive engines. If, as is ordinarily the case, the engine fires properly so that the shaft 13 continues rotation and accelerates in the direction in which it has been started no difiiculty results and the cranking action has been satisfactorily effected. But it occasionally happens that sparking occurs in the wrong cycle so that the shaft 13 is accelerated in reverse direction, in which case the clutch pin 14 acting upon the faces 32 will correspondingly rotate the shaft 27 and throw the crank arm 28 backward with great violence frequently breaking the arm or causing other serious injury-to the operator. To remedy this serious fault in cranking devices and make impossible the unfortunate result-s attendant upon misfiring, we have provided upon the disk 20 means whereby at the moment that the shaft 13 starts to rotate in backward direction, thereby tending to rotate in the same direction the shaft 15 is knurled or provided with clutching means thereon, a drum rotatably mounted on and movable along said shaft, means cooperating with the drum to move it along said shaft when the drum is rotated backwardly, a starting element adapted to cooperate with the clutching means on the shaft to rotate the same in a direction to start the engine, and means on said starting element working within said drum and engaging the inner periphery of said drum in a plurality of places whereby rotation of said starting element and engaging means in reverse direction will cause the drum to rotate therewith and thereby to unclutch the starting element from the shaft.

2. An explosive engine having a shaft with clutching means thereon, a drum rotatably mounted on and movable along said shaft, a starting element adapted to cooperate with the clutching means on the shaft to rotate the same in a direction to start the engine, means on said starting element working within said drum and engaging the innor periphery of said drum in a plurality of places whereby rotation of said starting element and means in reverse direction willcause the drum to rotate therewith, and means cooperating with said drum to hold the same from rotation with said starting element in the starting direction and to force said drum outwardly on the shaft when the drum is rotated in reverse direction.

3. An explosive engine having a shaft with clutching means thereon, a drum rotatably mounted on and movable along said shaft, means cooperating with the drum to move it along said shaft when the drum is rotated backwardly, a starting element adapted to cooperate with the clutching means on the shaft to rotate the same in a direction to start the engine, a disk mounted on said starting element so as to rotate freely within the drum but be constrained to move longitudinally of the engine shaft therewith, and means on said disk engaging the inner periphery of said drum in a plurality of places whereby rotation of said disk in reverse direction will cause the drum to rotate with the disk and thereby to unclutch the starting element from the shaft.

t. An explosive engine having a shaft with clutching means thereon, a drum rotatably mounted on and movable along said shaft, means cooperating with the drum to move it along said shaft when the drum is rotated baekwardly, a starting element adapted to cooperate with the clutching means on the shaft to rotate the same in a direction to start the engine, a disk mounted on said starting element so as to rotate freely within the drum but be constrained to move longitudinally of the engine shaft therewith, and a multiplicity of baekwardly pointing dogs pivoted to said disk so as to engage the inner periphery of said drum and cause the same to rotate with the disk when the dlsk is rotated in reverse direction and thereby to unclutch the starting element from the shaft.

5 An explosive engine having a shaft with clutching means thereon, a drum rotatably mounted on and movable along said shaft, said drum being formed with a roughened engaging surface on the inner periphery thereof, means cooperating with the drum to move it along said shaft when the drum is rotated backwardly, a starting element adapted to cooperate with the clutching means on the shaft to rotate the same in a direction to start the engine, a disk mounted on said starting element so as to rotate freely within the drum but be constrained to move longitudinally of the engine shaft therewith, and a multiplicity of backwardly pointing dogs pivoted to said disk so as to engage said roughened surface and cause the drum to rotate withthe disk when the disk is rotated in reverse direction and thereby to unclutch the starting element from the shaft.

6. An explosive engine having a shaft provided with an outwardly extended clutching end, a drum rotatably mounted on and movable along said shaft, means for engaging said drum to cause the same to move outwardly along the shaft when the drum is reversely rotating, a cranking shaft carrying a disk mounted in said drum so as to rotate freely therein but be constrained to move longitudinally of the engine shaft therewith, means in said disk adapting the cranking shaft to be clutched to the engine shaft to rotate the same in a direction to start the engine, and means on said disk engaging the inner periphery of said drum whereby rotation of said disk in reverse direction will cause the drum to rotate with the disk and thereby to unclutch the shafts.

7. An explosive engine having a shaft provided with an outwardly extended clutching end, a drum rotatably mounted on and movable along said shaft, a cranking shaft carrying a disk mounted in said drum so as to rotate freely therein but be constrained to move longitudinally of the engine shaft therewith, means in said disk adapting the cranking shaft to be clutched to the engine shaft to rotate the same in a direction to start the engine, means on said disk engaging the inner periphery of said drum whereby rotation of said disk in reverse direction will cause the drum to rotate with the disk, and stationary means adapted to cooperate with said drum when the same is reversely rotated to unclutch said shafts at the beginning of said reverse rotation.

8. An explosive engine including a shaft, a stationary member, a drum rotatably and slidably mounted on the-shaft having means on the inner peripheral edge thereof to cooperate with said stationary member and hold said drum from rotation in one direction and force said drum outwardly on the shaft when the drum is rotated in reverse direction, a hand crank carrying a disk adapted to form connection with said shaft to rotate the same in a direction for starting the engine, and spring-pressed fingers on said disk cooperating with the drum so as to permit the disk to rotate within the drum in said active direction but acting to clutch the drum and disk to rotate together in reverse direction and thereby disconnect said crank when the engine mis-fires and makes a back stroke.

9. An explosive engine including a shaft, a stationary member, a drum rotatably and slidably mounted on the shaft having means on the inner peripheral edge thereof to cooperate with said stationary member and hold said drum from rotation in one direc tion and force said drum outwardly on'the shaft when the drum is rotated in reverse direction, the outer portion of said drum being interiorly grooved longitudinally thereof, a hand crank carrying a disk adapted to form connection with said shaft to rotate the same in a direction for starting the engine, and spring-pressed fingers on said disk cooperating with said grooved portion so as to permit the disk to rotate within the drum in said active direction but acting to clutch the drum and disk to rotate together in reverse direction and thereby disconnect said crank when the engine mis-fires and makes a back stroke.

In testimony whereof we affix our signa tures in presence of'two witnesses. I FRANK BRAYER.

SIDNEY L.

Vitnesses V a F. A. VVHITELEY,' H. A. BOWMAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

